Explosives

Question 1

Initial response for explosion incident is:

Answer 1

• Gain control of the scene
  Preservation of life and treatment of casualties first priority
  Identify victims
  Important to have forensic awareness training

Question 2

Post explosion incident scene control:

Answer 2

• Gain control of scene
• Place cordon around scene, radius of 100-200m
• Point of explosion would be the center point
• Radius will depend on debris field and environment

Question 3

Purpose of Cordon is:

Answer 3

• Preserve the scene
• Allows systematic and effective recovery of evidence
• Control access and movement
• Allow forensic recovery to happen in undisturbed and safe way

Question 4

Goals for recovery after explosive incident is:

Answer 4

• Determine cause of explosion
• Construction, components and functioning of explosive device
• Nature of explosive charge
• Recover physical and chemical evidence

Question 5

Place recovered items from explosion in airtight nylon bag:

Answer 5

• Time and date of recovery
• Recovery location
• ID of person recovering evidence
• Unique identifier
• Log item out of scene

Question 6

Two essential components of explosive device:

Answer 6

• Explosive charge

- Means to initiate charge

Question 7

Parts of explosive device may include:

Answer 7

• Explosive train/ various explosives to achieve detonation
• Electrical components/ wires, batteries, leds
• Timing devices
• Shrapnel/ nails and screws
• Sensors/ proximity and movement
• Switches/ mechanical and electronic

Question 8

Types of explosions:

Answer 8

• Mechanical/ buildup of pressure until vessel fails
• Chemical/ chemical reaction from heat, light gases
• Nuclear/ splitting or fusing of atoms; energy from heat and X-rays
• Electrical/ high energy arcs that generate heat for explosion;energy of
  reaction energizes atoms of target material until breakdown occur
  Ex: lighting, short circuit

Question 9

Primary effect of explosion:

Answer 9

• Blast wave (pressure)
• Fragmentation
• Incendiary (thermal component)

Question 10

Blast wave is:

Answer 10

• Pressure wave that radiates outward from point of explosion
• May be produced by expanding gases and combustion
• Causes the most damage
• Radiates outward rapidly; distance increases, speed and pressure drop
• At point of explosion, vacuum created air is pushed away by pressure
  wave

Question 11

Fragmentation is:

Answer 11

• Device broken into pieces by blast or when objects are attached
  to the outside or included inside a device to increase blast
  damage to kill and injure personnel
• Common in IEDs and hand grenades
• Low explosives (cause large rectangular shaped fragments)
• High explosives ( cause small triangular shaped fragments)

Question 12

Fragmentation types are:

Answer 12

• Primary (shrapnel or fragments from initial explosion)
• Device casing or objects attached to outside

Secondary (when primary fragments stroke something and impart directional energy to that object)

Question 13

Primary effect of explosion:

Answer 13

Incendiary Thermal Effect

• High temperature from explosion
• Maybe localized at point of explosion
• Can be done remotely from hot fragments hurled outward from point of explosion
• Most incendiary explosions will cause incendiary effect of some type

Question 14

Improvised Explosive Device (IED) consist of:

Answer 14

• Detonator
• Booster
• Main Charge

Question 15

Elements of IEDs:

Answer 15

• Explosive
• Initiation System
• Container
• Binding material
• Shrapnel and other hazardous material

Question 16

IED components are:

Answer 16

• Switch
• Initiator
• Explosive
• Power source

Question 17

Essential components of explosive device:

Answer 17

• Explosive charge
• Means of initiating charge
• Post explosion; basis of forensic recovery.

Question 18

Four major elements of explosion:

Answer 18

• Rapid increase in gas pressure
• Confinement of pressure
• Rapid release of that pressure
• Damage or change to the confining structure of the vessel

Question 19

Post explosion recovery:

Answer 19

• High explosive (shattering ability, damage such as irregular fracture provide evidence of detonating explosive; plastic melting and microscopic cratering
• Deflagrating explosives (recovered post explosion in unreacted state; like propellants in pipe bombs; rupture of vessel lead to quenching of reaction resulting in unconsumed explosive charge available for recovery.

Question 20

Recovery of evidence from bodies:

Answer 20

• Types of injuries received by victims
• Shrapnel (fragments from explosive device may identify it)
• Victims should be examined and X rayed locate, recover and ID source
• Chemical examinations may ID explosive device

Question 21

Results of explosion:

Answer 21

• Structural damage
• Broken gas lines
• Broken water lines
• Downed electrical lines
• Release/ production of toxic materials
• Biological issues

Question 22

Primary blast injuries known as PBIs:

Answer 22

• Caused by large pressure differential of blast wave
  shearing, implosion and acceleration/deceleration injuries
• Hollow medium filled tissues such as ears, lungs and GI at higher risk
  then solid organs
• Total body disruption (TBD); amputation
• Usually occur to victims in close proximity(suicide bombers)

Question 23

Secondary blast injury (SBI):

Answer 23

• Caused by objects accelerated by explosion
• Velocity (injury potential of projectiles based on magnitude)
• Weight of projectile, distance from source of explosion
• IEDs employ additives such as screws and nails for similar effect
• Account for majority of injuries in survivors

Question 24

Modes of activation:

Answer 24

• Delay activation
• Victim activation
• Command activation

Question 25

An explosion is:

Answer 25

A rapid expansion of gases resulting from a chemical or physical action that produces a pressure wave.

Question 26

Tertiary Blast injury (TBI) is:

Answer 26

• Result of displacement of victim by blast wind.
• Victim propelled along ground, resulting in contusive blunt trauma
• Victim launched through air; may collide with stationary objects.
• Severity of TBI depend on proximity and magnitude of blast.

Question 27

Quaternary Blast injury :

Answer 27

Result from variety of blast effects
- Burns, chemical and toxic dust poisoning, radiation exposure,
crush injury due to building collapse